Engraving machine



1967 H. SCHMIDBAUER ETAL 3,296,700

ENGRAVING MACHINE 2 Sheets-Sheet 1 Filed Aug. 20, 1964 wwmwas HA N5 5cHM/05Az/5R BY CfiR/ST/A/V 1967 H. scHMlDBAuER ETAL 3 ENGRAVING MACHINE Filed Aug. 20, 1964 2 Sheets-$heet 2 51 %V% N TQRS HANS SCHM/DBAUER CHRLST/A/V CLAAS y WndmfiW United States Patent 3,296,700 ENGRAVING MACHINE Hans Schmidbauer, Kolpingstrasse 5, and Christian Qlaas, Beethovenstrasse 13, both of Singen, Hohentwiel, Germany Filed Aug. 20, 1964, Ser. No. 390,910 Claims priority, application Germany, Aug. 21, 1963, Sch 33,738 11 Claims. (Cl. 33-44) The invention relates to an engraving machine, particularly, a machine for engraving or duplicating milling of curved workp ece surfaces.

The object of the invention is to conceive an engraving machine such that the inner surfaces of curved workpieces, e.g., of rings can be engraved, and to realize a construction in which apart from rotary tools, like spindles with end-milling cutters, fixed tools like diamond cutters can be used. Using the latter tools which exert a relatively high pressure on the material being engraved, care must be taken that the construction is so solid, simple and reliable in operation that by exerting a sufliciently high pressure on the tool a satisfactory impression is obtained even in rather hard workpieces.

The invention uses engraving machines with a toolholder fixed displaceably in a first plane to the frame so that the depth of penetration into the workpiece can be adjusted, and with a workpiece holder moved by means of a control rod scanning the stencil in two planes at right angles to each other and to the first plane.

Usng such engraving machines, the problem is solved according to the invention in that the control rod is supported in a Cardan joint connected with the frame, one end of the control rod is provided with a scanner and the other end with a ball supported free from play in a bearing box attached to the workpiece holder, the workpiece holder itself being connected free from play by means of balls or bfll bearings with the frame.

With such a type of machine, one achieves with minimum expense for design and production and with a minimum number of bearings, an operation such that concave and convex surfaces on the inner or outer side of a hollow body can be engraved. The control rod supported with a spacing from its ends in a Cardan joint enables the transmission in two planes at right angles when the stencil is scanned. Dependent on whether the workpiece has straight or curved surfaces, this motion is then transformed in such a way that the workpiece is engraved with constant depth of impression.

The invention provides a simple means allowing the variation of the transmission ratio involved in scanning the stencil and transmission to the workpiece, i.e., that the Cardan joint can be adjusted as to its spacing from the scanner tip, for instance, by a guide column.

Thus, it is possible by mediation of a bearing that characters of equal height are transmitted to the workpiece, once from a large, once from a small stencil, since any arbitrary adjustment can be achieved by the infinitely variable transmission.

A special type of engraving machine of our invention which is particularly suited to engrave curved surfaces on scanning a plane stencil is essentially characterized by the fact that for engraving curved surfaces, the workpiece holder is connected by a printing table with the control rod and a tension cable looped around the shaft of the workpiece holder and fixed to the printing table on both sides of the shaft, to transform the straight motion of the printing table into a rotary motion of the workpiece holder in this plane a guide piece with guide faces is fixed to the printing table to transmit by means of a feeler the ice motion of the printing table in the other plane to the workpiece holder.

Thus, in this embodiment, a printing table is inserted between stencil and workpiece which has the task to transform the contours being scanned in one plane in such a way that they are transmitted to curved surfaces which are engraved in conformity with the characters of the plane stencil or its contours with the same depth of impression.

The guide piece fixed on the printing table is usefully conceived with a bore in which one end of the feeler is supported, the other end of which ends as a ball which is supported free from play in a bearing box connected with the workpiece holder.

This type, too, requires a minimum of bearings and fine mechanical parts for a smooth and accurate transmission of the most intricate contours and curves.

A further embodiment of an engraving machine of our invention particularly used to engrave the inner surface of rings is characterized in that for engraving the inner surface of rings, the shaft of the workpiece holder is supported in a bracket resistant to bend'ng which is connected free from play by means of ball bearings with the frame, swiveiing in two planes at right angles.

Supporting the workpiece holder in a bracket allows the transmission of high compressive stresses from the tool to the workpiece. Hence, in this type of machine, tools can be used which are not rotating, e.g., diamond points. Other toois like milling-cutter spindles are in any case unsuited to engrave the inner surfaces of rings, since they require too much space to be used inside of rings, e.g., wedding rings.

Another useful construction is achieved in that the bracket is conceived Ushaped and at the end of the lower leg, the ball of the control rod is supported in the bearing box of the bracket, while the other end is fixed to the center of a crossover bar, the extremities of which are connected by ball bearings with the frame, so that the tension cable allows the rotation of the crossover bar and swiveling motion of the workpiece holder.

The bracket swiveling in two planes at right angles makes it possible by moving in one plane that the shaft will rotate with the workpiece, transforming a linear motion into a rotary one, and by swiveling at right angles to the first plane, that the respective motion of the scanner on the stencil is transmitted.

A high compressive stress exerted by the tool can be transmitted owing to the fact that the bearing of the shaft of the workpiece holder is accommodated in a bearing block which is rigidly fixed to the crossover bar and connected by means of a ball bearing with the U-shaped bracket.

To achieve an appropriate fixation of the workpiece, it is essential that a cable pulley with a slit receiving the tension cable is provided on one side of the bearing block near the center piece of the U-shaped bracket, while on the other side, the location for the workpiece is provided. 7

Thus, on engraving, a compressive stress exerted by the tool on the workpiece is taken in the bearing block and transmitted from the bearing block to the frame.

To achieve a reliable and good fixation of the workpiece, it has proved useful to locate it in a cup-shaped casing, the cover of which is provided with tightening screws to locate the ring being engraved.

If the hollow body allows the introduction of a spindle, which is possible with a certain inclined position of the hollow body relative to the center line of the spindle, it is useful that in the toolholder is a spindle carrying at the end a locating fixture for the end-milling cutter.

When stationary tools are used, for example, diamond 3 points, it is essential that the toolholder is a one-arm lever ending on one side in a bearing connected with the frame, and its other side should rest by way of a roller on a rotating eccentric cam, and its center part should carry the tool projecting into the ring.

The application of an eccentric cam makes it possible to remove the tool from the workpiece by traversing a lever which rotates the roller connected with the eccentric cam. Conversely, it is possible that with a lever of suitable length, the loading of the tool is effected by the Weight of the lever which is otherwise lifted by the eccentric cam.

To enable a coarse adjustment of the tool to the workpiece, it is essential that the bearing of the one-arm lever be connected by a set screw with the frame, i.e., on one side of the frame.

Owing to these measures, an easy handling of the engraving machine is achieved, together with a great reliability in operation and a moderate constructional expenditure.

Embodiments of the invention are shown in the drawing. From the drawing and the respective description further characteristics of the invention become evident.

FIGURE 1 shows diagrammatically the construction of our engraving machine with a planar stencil, a ring being engraved, and a rotary tool.

FIGURE 2 represents a possible construction of the guide piece on the printing table when the scanning motion on the stencil is transformed into a respective motion of the workpiece having convex or concave surfaces.

FIGURE 3 shows a further construction of the guide iece. p FIGURE 4 is a fragmental perspective view in elevation of the U-shaped bracket and of the rear of the workpiece holder in an engraving machine with a stationary tool.

FIGURE 5 represents a fragmental perspective front view of the workpiece holder, after removal of the cover, in which the workpiece is fixed.

FIGURE 6 is a fragmental perspective view of the toolholder with the tool in position within a workpiece being engraved.

FIGURE 7 is a total front view in elevation of an engraving machine according to FIGURES 4-6 with sevwork ieces shown.

l lGUl E 8 is a detail of FIGURE 7, showing the U- ha ed bracket sus ended in points. S F IGURE 1 shoia vs a workpiece 1 which is rotated in the direction of arrows 3 when the printing table 16 moves to and fro in the direction of the arrows 2. Moving in the direction of the arrows 3 and at right angles to the plane of, paper the tool holder 5, as ad usted to its depth of impression in the sense of the arrow 4, will engrave with its rotary tool, e.g., by a milling-cutter spindle 6 (see FIGURES l and 2), the inner face of round workpiece 1 in conformity with the movement of a scanner 8 that is fixed to a control rod 9, on a stencil 10. On the stencil 10, contours 11 are present which should be transmitted areally to the inner surface of a workpiece 1, such as a wedding ring. The stencil s fixed between mounting supports 12, 13 and displaced in the direction of the arrows 14, 15 to such an extent that the beginning and end of the characters be ng transmitted can be engraved into the workpiece 1 1n the appropriate position. Between the scanner 8, the control rod 9 and the milling-cutter spindle 6 of the workpiece holder 5, printing table 16 is inserted to which a guide piece 17 is fixed. If it should be desired to engrave a plane surface of some workpiece, such workpiece 1 would be fastened to the printing table 16.

The motion of the printing table 16 imparted by the control rod 9 is effected by means of a Cardan joint 18. This Cardan joint, too, is connected by means of the mounting supports 12', 13' with the frame of the machine, or the mounting supports 12', 13 represent a frame serving as a reference plane for the different motions. With the aid of the Cardan joint, two planes at right angles designated by the arrows 14', 15' are transmitted to the printing table 16, while the third plane at right angles to the two former ones is indicated by the arrows 4. At the printing table on arms 19, fixtures 20 are provided between which a tension cable 21 is tightened which is led in a loop 22 round a shaft 23 of a workpiece holder 24 (see FIGURES 2 and 3 in View of FIGURE 1). When the printing table 16 moves in the direction of the arrows 14', this straight motion is transformed into a rotary motion of a workpiece holder 24 and the workpiece 1 in the direction of the arrows 3, in a manner known in itself. The motion of the printing table 16 is transmitted by the scanner 8 of the control rod 9 via the Cardan joint 13, making a two-arm lever of the control rod 9 to ball 25 which forms the other end of the control rod 9. This ball 25 is fixed free from play in a bearing 'box 26 (see FIGURES 2 and 3) that is rigidly connected with the printing table 16. The Cardan joint 18 with its swivel axes 27, 28 is connected free from play with the mounting supports 12', 13' and the frame, so that on tracing the characters, i.e., the contours 11 of the stencil 10, this motion is transformed free from backlash into a motion of the printing table 16 in the direction of the arrows 14, 15'.

While the transformation of the straight motion in the sense of the arrows 14' of the printing table 16 into a rotary motion in the sense of the arrows 3 by means of the tension cable 21 has been described above, it will now be described, how the motion of the printing table in the direction of the arrows 15 is transformed into the respective motion of the workpiece 1. On the printing table 16, guide piece 17 is provided having a sloping guide face 29 which is scanned by a feller 30. Dependent on the inclination of this guide face 29 to the base of the printing table 16, an enlargement or reduction is effected when the motion is transmitted. The feeler 30 is connected with the workpiece 1 and effects its motion in conformity with the motion of the scanner 8 on the stencil 10.

Particularly from FIGURE 3, it is evident that the feeler 30 is accommodated free from play with one end 31 in a bore 32 of the guide piece 17. Its other end ends in a ball 33; bearing box 34 encases the ball 33 without clearance. The bearing box 34 is connected with the workpiece holder 24.

From FIGURE 3, it is evident that a sidewise or lengthwise motion of the printing table 16 perpendicularly to the plane of the paper of the drawing rotates the workpiece 1 by actuating the tension cable 21 and a motion of the printing table 16 in the direction of the arrows 14 to shift the workpiece holder 24 at right angles to the plane of the paper of the drawing (compare FIGURE 2). By means of sliding bearing box 26, an exact transmission of these motions is obtained.

Moreover, it is essential that the printing table 16 be supported on balls 37, so that it can be displaced very easily and free from play. Instead of these balls 37, roll er or ball bearings can be used.

In FIGURES 4 to 8, the same numerals are generally used for the corresponding parts. Instead of the printing table 16, a table bracket 38 (see FIGURES 4 and 8) that is: resistant to bending is positioned to receive the workpiece holder 24 (casing 54) therein (see FIGURE 8) and cooperate with the control rod 9 (see FIGURE 7). This bracket 38 is resistant to bending and, if it is of U-shape, is provided at its lower leg 39 with the bearing box 26 for the ball 25 that is fixed to the upper end of the control rod 9. Upper leg 40 of bracket 38 is interrupted by a ball bearing mount 41 (see FIGURES 4 and 8). This ball bearing mount 41 allows bearing block 43 (see FIG- URE 8) to be swingably suspended on a mounting bar 42 that is swiveled with the workpiece holder 24 for movement in the direction of arrows 14" of FIGURE 7, i.e., perpendicularly of the plane of the paper of the drawing (see FIGURE 8), when the scanner 8 is equally moved to and fro in the direction of the arrows 14". If the scanner 8 is moved in the direction of the arrows 15" of FIGURE 7 the bracket 38 swivels in the same direction. The upper leg part 46 of the bracket 38 is rigidly connected with a crossover 47 (see FIGURES 7 and 8). This crossover 47 is pivotally or swivelly connected by end point suspensions 48 (see FIGURE 7) with the frame and columns or mounting supports 12', 13', so that the bracket 38 is now able to swivel with the crossover bar 47 in the direction of the arrows 49 of FIGURE 7, i.e., perpendicularly of the plane of the paper of the drawing. Springs 50 provided on both sides of the mounting bar 42 (see FIGURES 4 and 7) relieve the ball bearing 41 of the weight of the bearing block 43. The bearing block 43 accomodates the shaft 23 of the workpiece holder 24. To one side of the workpiece holder 24, a cable pulley 51 (see FIGURES 4 and 8) is attached which has a slit 52 receiving the tension cable 21. The tension cable 21 is held in fixtures (see FIGURES 1 and 4) mounted on arms 20. These arms 20 are arranged bilaterally spaced from the bearing block 43 (see FIGURES 4 and 8). When the bracket 38 moves in the direction of the arrows 15" of FIGURE 7, the shaft 23 (see FIGURES 4 and 8) is rotated with the aid of the cable pulley 51, since the mounting bar 42 (see FIGURES 4, 7 and 8) is prevented from joining in this motion.

By using the bracket 38 instead of the printing table 16 of FIGURE 1, it is possible that the tool, for instance, a diamond can exert a strong pressure on the workpiece 1.

The workpiece 1, itself, is fixed in the workpiece holder 24, this workpiece holder being formed by a cup-shaped casing 54 (see FIGURES 4,5, 6 and 7) the cover 55 (see FIGURES 5 and 7) of which is provided with tightening screws 56 which fix the workpiece 1. Knurled nuts or screw heads 57 (see FIGURES 5 and 6) are tightened to secure the cover on the casing 54.

The toolholder 65a is carried by a lever arm 65 of a crossover 58 (see FIGURES 5 and 7) which can be displaced by means of set or thumb screws 59 along the columns 12', 13. A lower, vertically-adjustable crossover 60 which can be equally displaced along the columns 12', 13, is again provided with set or thumb screws 59 and accommodates sleeve 9a of the Cardan joint 18. On shifting this lower crossover 60 in the direction of the arrows 61 of FIGURE 7, the transmission ratio is varied. It can be infinitely varied from 1:3 to 1:40. This variation of the transmission and copying ratio, respectively, is important if one intends to use, as indicated at the left-hand bottom of FIGURE 7, various workpieces 1 of very different diameters. On upper crossover 58 of the toolholder, an eccentrically supported roller 62 (see FIGURE 7) is provided which can be shifted by means of a swing handle 63. On this roller 62, a roller 64 rests which is fixed to the end 66 of a one-arm lever 65 (see also FIGURE 6) whose other end 67 is supported swiveling in a bearing 68 of the upper crossover 58. Approximately in the center of crossover 58, a tool 69 is fastened (see FIGURES 5 and 6). As shown in FIGURE 5, pinlike tool 69 is provided at its end with an engraving diamond 70. As shown in FIGURES 5 and 7, the entire crossover 58 can be swung out on its collar 58a on column 12' so as to ensure free access to the workpiece holder. It will be noted that the bracket 38 is connected free from play by means of ball bearings to the frame," and is swiveled in two planes or lines at right angles.

The field of application of this invention includes all instances where, with a rotary or a fixed tool, workpieces having straight, convex or concave surfaces are to be engraved, independently of whether these convex or concave surface are inner or outer faces. The essential feature is that it is possible to vary infinitely the transmission ratio and to adjust the depth of penetration of the tool and the pressure exerted with the latter, and

that the whole device works with few bearings, i.e., does not need much maintenance, is very reliable in operation, easily operable and accessible, does not require much space, works accurately and with precision, and enables the transmission from stencils of the most different shapes and sizes to always the same or similar workpieces with a minimum expenditure of attendance.

What we claim is:

1. In an engraving machine having a tool for inscribing a workpiece in accordance with the configuration of a stencil and provided with an elongated frame, a support member adjacent one end of the frame for positioning the stencil thereon, a workpiece holder operatively-mounted adjacent the other end of the frame for positioning the workpiece thereon, a movement transmitting member op eratively-carried by the frame adjacent the other end thereof for back and forth movement along one line and for back and forth movement along another line at right angles to the one line, means operatively-connecting said movement transmitting member to said workpiece holder to impart movement to said holder induced by back and forth movement thereof along the two lines; control rod means having a scanner at a forward end thereof for tracing the stencil, having an intermediate Cardan joint mounted on an intermediate portion of the frame, and having a universal ball joint connection at a back end thereof with said movement transmitting member for moving said movement transmitting member in accordance with tracing of the stencil by said scanner; an engraving tool holder mounted adjacent the other end of the frame in alignment with said workpiece holder to position the tool in engagement with the workpiece, said operatively-connecting means including a tension cable carried by said movement transmitting member and connected with said workpiece holder for actuating said holder in accordance with back and forth movement of said movement transmitting member along the one line, and said operatively-connecting means including swingably-mounted means for enabling movement of said workpiece holder in accordance with back and forth movement of said movement transmitting member along the other line.

2. In an engraving machine as defined in claim 1 wherein said Cardan joint has means for adjustably-mounting it on the frame to adjust its distance from said scanner.

3. In an engraving machine as defined in claim 1 wherein, said movement transmitting member has a sloped guide extension, and said swingably-mounted means includes a feeler that is operatively-connected between said workpiece holder and said movement transmitting member for movement along said sloped guide extension to transmit back and forth movement of said member along the other line to said workpiece holder.

4 In an engraving machine as defined in claim 3 wherein, said guide extension has an open end bore therein, and said feeler has one end portion slidably-positioned within said bore and has an opposite end portion provided with a ball and socket connection with said workpiece holder.

5. In an engraving machine as defined in claim 1 where in, said workpiece holder has a shaft secured thereto for rotatably-mounting it with respect to said movement transmitting member, said movement transmitting member has a pair of spaced-apart supports, and said tension cable is looped around said shaft and securely connected at its opposite ends between said supports for translating back and forth movement of said movement transmitting member along the one line into clockwise and counterclockwise rotational movement of said workpiece holder.

6. In an engraving machine as defined in claim 5 wherein, said movement transmitting member also has a sloped guide extension, and said swingably-mounted means includes a feeler that is operatively-connected between said workpiece holder and said movement transmitting member for movement along said sloped guide extension to transmit back and forth movement of said member along the other line to said workpiece holder.

7. In an engraving machine as defined in claim 1 wherein, said movement transmitting member is a U-shaped bracket resistant to bending, said swingable-mounted means is an arm swiveling said bracket with respect to the frame, and an arm suspends said workpiece holder from said bracket.

8. In an engraving machine as defined in claim 7 wherein, said swiveling arm is a crossover bar pivotally-mounted within the other end of the frame, and ball bearing means connects said arm suspending said workpiece holder with said U-shaped bracket.

9. In an engraving machine as defined in claim 1 for a workpiece in the nature of a ring wherein, said workpiece holder has a shaft secured thereto for rotatablymounting it with respect to said movement transmitting member, said movement transmitting member has a pair of spaced-apart supports, said tension cable is looped around said shaft and connected at its opposite ends between said supports for translating back and forth movement of said movement transmitting member along the one line into clockwise and counterclockwise rotational movement of said workpiece holder, said work-piece hold er has a cup-shaped casing and an end member, and said end member has tightening screws for locating the ring therein.

10. In an engraving machine as defined in claim 1 wherein, a lever arm is swiveled at one end thereof on the frame, said tool holder is secured on said lever arm intermediate its ends, roller means is mounted on the other end of said lever arm, and an eccentric cam having an operating arm is carried by the frame in operating engagement with said roller means.

11. In an engraving machine as defined in claim 1 for a workpiece in the nature of a ring wherein, said workpiece hold-er has a shaft secured thereto for rotatably mounting it with respect to said movement transmitting member, said movement transmitting member has a pair of spaced-apart supports, said tenson cable is looped around said shaft and connected at its opposite ends be tween said supports for translating back and forth movement of said movement transmitting member along the one line into clockwise and counterclockwise rotational movement of said workpiece holder, said workpiece holder has a cup-shaped casing, a lever arm is adjustably mounted and swiveled at one end thereof on the frame, said tool holder is secured on said lever arm intermediate its ends, a roller is operatively-carried on the other end of said lever arm, a rotating eccentric cam is operatively-carried by the frame in engagement with said roller, and operating means is connected to said cam for moving it on said roller.

References Cited by the Examiner UNITED STATES PATENTS 37,235 12/1862 Ives 33-24 486,210 11/1892 Hope 33-22 815,233 3/1906 Terrell 90-13.1

2,562,269 7/1951 Gruettner et a1 3324 LEONARD FORMAN, Primary Examiner.

ISAAC LISANN, Examiner.

HARRY N. HAROIAN, Assistant Examiner. 

1. IN AN ENGRAVING MACHINE HAVING A TOOL FOR INSCRIBING A WORKPIECE IN ACCORDANCE WITH THE CONFIGURATION OF A STENCIL AND PROVIDED WITH AN ELONGATED FRAME, A SUPPORT MEMBER ADJACENT ONE END OF THE FRAME FOR POSITIONING THE STENCIL THEREON, A WORKPIECE HOLDER OPERATIVELY-MOUNTED ADJACENT THE OTHER END OF THE FRAME FOR POSITIONING THE WORKPIECE THEREON, A MOVEMENT TRANSMITTING MEMBER OPERATIVELY-CARRIED BY THE FRAME ADJACENT THE OTHER END THEREOF FOR BACK AND FORTH MOVEMENT ALONG ONE LINE AND FOR BACK AND FORTH MOVEMENT ALONG ANOTHER LINE AT RIGHT ANGLES TO THE ONE LINE, MEANS OPERATIVELY-CONNECTING SAID MOVEMENT TRANSMITTING MEMBER TO SAID WORKPIECE HOLDER TO IMPART MOVEMENT TO SAID HOLDER INDUCED BY BACK AND FORTH MOVEMENT THEREOF ALONG THE TWO LINES; CONTROL ROD MEANS HAVING A SCANNER AT A FORWARD END THEREOF FOR TRACING THE STENCIL, HAVING AN INTERMEDIATE CARDAN JOINT MOUNTED ON AN INTERMEDIATE PORTION OF THE FRAME, AND HAVING A UNIVERSAL BALL JOINT CONNECTION AT A BACK END THEREOF WITH SAID MOVEMENT TRANSMITTING MEMBER FOR MOVING SAID MOVEMENT TRANSMITTING MEMBER IN ACCORDANCE WITH TRACING OF THE STENCIL BY SAID SCANNER; AN ENGRAVING TOOL HOLDER MOUNTED ADJACENT THE OTHER END OF THE FRAME IN ALIGNMENT WITH SAID WORKPIECE HOLDER TO POSITION THE TOOL IN ENGAGEMENT WITH THE WORKPIECE, SAID OPERATIVELY-CONNECTING MEANS INCLUDING A TENSION CABLE CARRIED BY SAID MOVEMENT TRANSMITTING MEMBER AND CONNECTED WITH SAID WORKPIECE HOLDER FOR ACTUATING SAID HOLDER IN ACCORDANCE WITH BACK AND FORTH MOVEMENT OF SAID MOVEMENT TRANSMITTING MEMBER ALONG THE ONE LINE, AND SAID OPERATIVELY-CONNECTING MEANS INCLUDING SWINGABLY-MOUNTED MEANS FOR ENABLING MOVEMENT OF SAID WORKPIECE HOLDER IN ACCORDANCE WITH BACK AND FORTH MOVEMENT OF SAID MOVEMENT TRANSMITTING MEMBER ALONG THE OTHER LINE. 